/* ============================================================
   golden.css — 黄金螺旋拼图 / 自然卡片 / 全屏沉浸阅读
   （斐波那契教学页面 · 样式封装 part 4）
   ============================================================ */

/* ---------- Golden spiral card ---------- */
.spiral-card {
  text-align: center;
  background: var(--card);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow);
}
.spiral-card svg { width: 100%; max-width: 420px; }

/* ---------- Golden spiral puzzle ---------- */
.puzzle-wrap { display: flex; flex-direction: column; align-items: center; gap: 18px; max-width: 100%; }
.puzzle-board {
  position: relative;
  border-radius: 8px;
  background:
    linear-gradient(rgba(255,255,255,0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.04) 1px, transparent 1px),
    var(--bg-2);
  background-size: 30px 30px;
  border: 1px solid var(--card-border);
  box-shadow: var(--shadow);
  touch-action: none;
  user-select: none;
}
.target-slot {
  position: absolute;
  border: 1px dashed rgba(251,191,36,0.35);
  border-radius: 4px;
  background: rgba(251,191,36,0.06);
  z-index: 1;
}
.target-slot.filled { border-color: transparent; background: transparent; }
.piece-shape {
  position: absolute;
  border-radius: 4px;
  background: linear-gradient(145deg, rgba(24,33,54,0.95), rgba(30,42,68,0.95));
  border: 1px solid rgba(255,255,255,0.22);
  box-shadow: 0 6px 18px rgba(0,0,0,0.5);
  z-index: 3;
  cursor: grab;
  transition: box-shadow 0.2s, transform 0.2s;
  touch-action: none;
}
.piece-shape.dragging { cursor: grabbing; box-shadow: 0 14px 34px rgba(0,0,0,0.65); }
.piece-shape.placed { cursor: default; box-shadow: 0 4px 10px rgba(251,191,36,0.15); }
.piece-shape.targets { border-color: var(--gold-1); box-shadow: 0 0 0 3px rgba(251,191,36,0.4); }
.piece-shape.locked { border: 1px solid rgba(251,191,36,0.8); }
.arc-svg {
  position: absolute;
  left: 0; top: 0;
  max-width: none;
  width: 100%; height: 100%;
  display: block;
  pointer-events: none;
  overflow: visible;
}
.piece-shape .size-label {
  position: absolute;
  right: 5px; bottom: 3px;
  font-size: 0.7rem;
  color: var(--muted);
  opacity: 0.85;
  pointer-events: none;
}
.puzzle-tray {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
  align-items: center;
  min-height: 44px;
  padding: 8px 12px;
  background: var(--card);
  border: 1px solid var(--card-border);
  border-radius: 12px;
  min-width: 0;
  width: 100%;
  max-width: 460px;
}
.puzzle-tray .tray-piece {
  width: 40px; height: 40px;
  border-radius: 6px;
  background: linear-gradient(145deg, rgba(24,33,54,0.95), rgba(30,42,68,0.95));
  border: 1px solid rgba(255,255,255,0.2);
  display: grid; place-items: center;
  font-weight: 700;
  font-size: 0.85rem;
  color: var(--text);
  cursor: grab;
  touch-action: none;   /* 关键：触屏上禁止浏览器滚动劫持，拖拽/点选才能生效 */
  box-shadow: 0 4px 10px rgba(0,0,0,0.4);
}
.puzzle-tray .tray-piece.dragging { opacity: 0.4; }
.puzzle-tray .tray-piece.used { opacity: 0.15; pointer-events: none; cursor: default; }
/* 触屏点选模式：选中高亮 / 放错抖动 */
.puzzle-tray .tray-piece.selected {
  border-color: var(--gold-1);
  box-shadow: 0 0 0 3px rgba(251,191,36,0.45), 0 4px 10px rgba(0,0,0,0.4);
  transform: scale(1.1);
}
@keyframes pieceShake {
  0%, 100% { transform: translateX(0); }
  20% { transform: translateX(-6px); }
  40% { transform: translateX(6px); }
  60% { transform: translateX(-4px); }
  80% { transform: translateX(4px); }
}
.puzzle-tray .tray-piece.shake { animation: pieceShake 0.45s ease; border-color: var(--pink); }
/* 触屏点选模式：选中托盘方块后，棋盘空格子高亮提示可点击 */
.puzzle-wrap:has(.tray-piece.selected) .target-slot:not(.filled) {
  border-color: rgba(45, 212, 191, 0.75);
  background: rgba(45, 212, 191, 0.08);
}
.puzzle-msg { font-size: 0.95rem; color: var(--muted); min-height: 24px; }
.puzzle-msg .done { color: var(--teal); font-weight: 700; }
.puzzle-reset { margin-top: 4px; }

/* ---------- Nature cards ---------- */
.nature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 24px;
}
.nature-card {
  background: var(--card);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 26px;
  transition: transform 0.3s, border-color 0.3s;
  position: relative; overflow: hidden;
  cursor: pointer;
}
.nature-card:hover { transform: translateY(-6px); border-color: var(--gold-1); }
.nature-card .emoji { font-size: 2.6rem; margin-bottom: 14px; }
.nature-card h3 { font-size: 1.15rem; margin-bottom: 8px; }
.nature-card p { color: var(--muted); font-size: 0.95rem; }
.nature-card::after {
  content: '';
  position: absolute; top: -40px; right: -40px;
  width: 90px; height: 90px; border-radius: 50%;
  background: radial-gradient(circle, rgba(251,191,36,0.15), transparent 70%);
}
.nature-card::before {
  content: '🔍 全屏阅读';
  position: absolute; right: 14px; bottom: 12px;
  font-size: 0.72rem; letter-spacing: 1px;
  color: var(--text);
  background: rgba(15,21,36,0.6);
  border: 1px solid var(--card-border);
  padding: 5px 12px; border-radius: 20px;
  opacity: 0; transform: translateY(6px);
  transition: opacity 0.3s, transform 0.3s;
  z-index: 2;
}
.nature-card:hover::before { opacity: 1; transform: translateY(0); }

/* 自然页入场改为「六个 emoji 卡先在界面中心浮现 → 散开到各自网格位并放大成框」，
   由 nature.js 用 GSAP 驱动；这里覆盖 base .reveal 的 3D 翻转，避免冲突。 */
#nature .nature-card.reveal { transform: none; }
#nature .nature-card.reveal:hover { transform: translateY(-6px); }

/* ---------- Nature 全屏沉浸阅读 ---------- */
.fs-overlay {
  position: fixed; inset: 0; z-index: 200;
  display: grid; place-items: center;
  opacity: 0; visibility: hidden; pointer-events: none;
  transition: opacity 0.45s ease, visibility 0.45s;
}
.fs-overlay.show { opacity: 1; visibility: visible; pointer-events: auto; }
.fs-bg {
  position: absolute; inset: -4%;
  background-size: cover; background-position: center;
  filter: blur(8px) brightness(0.6) saturate(1.1);
  transition: background-image 0.6s ease;
}
.fs-bg::after {
  content: '';
  position: absolute; inset: 0;
  background: linear-gradient(to bottom, rgba(15,21,36,0.35), rgba(15,21,36,0.72));
}
.fs-content {
  position: relative; z-index: 2;
  max-width: 680px; width: 90%;
  max-height: 82vh; overflow-y: auto;
  background: rgba(15,21,36,0.35);
  border: 1px solid rgba(255,255,255,0.12);
  border-radius: 22px;
  backdrop-filter: blur(14px);
  box-shadow: 0 30px 90px rgba(0,0,0,0.6);
  padding: 46px 48px 36px;
  text-align: center;
}
.fs-emoji {
  width: 84px; height: 84px; margin: 0 auto 18px;
  border-radius: 50%;
  background-size: cover; background-position: center;
  border: 2px solid rgba(251,191,36,0.6);
  box-shadow: 0 0 30px rgba(251,191,36,0.35);
  font-size: 2.4rem;
  display: grid; place-items: center;
  overflow: hidden;
}
.fs-title { font-size: 2rem; font-weight: 800; margin-bottom: 18px; letter-spacing: 1px; }
.fs-body {
  font-size: 1.08rem; line-height: 2;
  color: var(--text);
  text-align: justify; text-align-last: center;
}
.fs-dots { margin-top: 26px; display: flex; gap: 8px; justify-content: center; }
.fs-dot {
  width: 9px; height: 9px; border-radius: 50%;
  background: rgba(255,255,255,0.3);
  transition: background 0.3s, transform 0.3s;
}
.fs-dot.active { background: var(--gold-1); transform: scale(1.35); }

/* 左右切换 + 关闭 */
.fs-nav, .fs-close {
  position: fixed; z-index: 3;
  width: 52px; height: 52px;
  border-radius: 50%;
  border: 1px solid var(--card-border);
  background: rgba(15,21,36,0.5);
  color: var(--text);
  font-size: 1.8rem; line-height: 1;
  cursor: pointer;
  backdrop-filter: blur(6px);
  transition: background 0.3s, color 0.3s;
}
.fs-nav:hover, .fs-close:hover { background: rgba(251,191,36,0.25); color: var(--gold-1); }
.fs-close:hover { transform: scale(1.05); }
.fs-prev { left: 24px; top: 50%; transform: translateY(-50%); }
.fs-next { right: 24px; top: 50%; transform: translateY(-50%); }
.fs-close { top: 22px; right: 26px; }

/* 滑入动画 */
@keyframes fsSlideLeft  { from { transform: translateX(60px); opacity: 0; } to { transform: translateX(0); opacity: 1; } }
@keyframes fsSlideRight { from { transform: translateX(-60px); opacity: 0; } to { transform: translateX(0); opacity: 1; } }
.fs-content.anim-left  { animation: fsSlideLeft 0.4s ease; }
.fs-content.anim-right { animation: fsSlideRight 0.4s ease; }

@media (max-width: 700px) {
  .fs-content { padding: 40px 26px 30px; }
  .fs-prev { left: 10px; }
  .fs-next { right: 10px; }
  .fs-close { right: 14px; top: 14px; }
}

/* ---------- 手机端拼图适配 ---------- */
@media (max-width: 480px) {
  .spiral-card { padding: 16px 12px; }
  .puzzle-tray { padding: 8px 8px; gap: 6px; }
  .puzzle-tray .tray-piece { width: 38px; height: 38px; }
}